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Reverse Engineering | Industrial Electronics | Servo Repair

Making Schematics from Printed Circuit Boards - Why We Love Reverse Engineering

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There are many reasons why a PCB must be reverse engineered for a client however it is worth asking the question why do we love to reverse engineering printed circuit boards?

 

One of the biggest reasons we love to reverse engineer circuit boards is that we can learn a lot from the way a circuit board has been manufactured. We love the challenge of taking a circuit that serves a purpose but is now unsupported working out how it was made + then making a replacement.

 

Sometimes we need to clone or copy a circuit board in a process that involves duplication. Everything down to the routing of the traces is copied + this means that no mistakes are made, this is especially important for those circuit boards that are EMC Seismic + EMI qualified, routing the traces exactly like the original leaves little room for extra noise or crosstalk on the signalling. It’s in reverse engineering circuit boards like this that we learn how to make replicas of technology that might be dated or have modern equivalents + we have the challenge of finding out where to source parts from, how to manufacture mechanical parts + how to assemble the product.

 

When it comes to feature upgrades or adding something new we love to reverse engineer a circuit board as we are allowed the creativity to make something great again or to add features that the client longed for but could never have, both situations give us great pleasure using our industry knowledge for your advantage.

 

Reverse Engineering can often feel like a complex + detailed painting however in reality often circuits are patterns + the more you study them the more you recognise the patterns + the easier it is to reverse engineer the circuit. Many circuits have standard layouts (often found in the application note or datasheet) these circuits help us to draw schematics + layouts of your design. The simplicity of this approach is yet another reason why we love electronic reverse engineering.

 

To see some of our past projects check out our reverse engineering projects page.

Variable Frequency Drive (VFD) Repair

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Recently we were working on a variable frequency drive and this repair was a hot rush - meaning that an entire line in a factory was down, the need to repair the drive quickly and efficiently was of utmost importance.

 

Once the drive was received into our repair laboratory we started working on it immediately by diagnosing the issues and ordering the parts.

 

Once the parts were installed the next thing to do was to power up the VFD (Variable Frequency Drive) to see if the new parts solved the issue. Once powered the bus was not charging, we determined that there must be something else wrong. After a full tear down of the drive our engineers drew schematics to work out how power was getting to the bus. We discovered the voltage was coming through a precharge resistor into the bus which once it was charged the SCRs (Silicon Controlled Rectifier) would fire and the voltage would be on the bus. The problem was we still had no voltage on the bus. Realizing that it was the precharge resistor that had blown we traced this back and found that although the connector looked functional in reality it was blown inside.

 


Once this was repaired the bus was charged. But then one of the bus capacitors blew which was probably the cause of the blown precharge resistor in the first place. After replacing this resistor from our large inventory of in house stocked components we were able to try running the low voltage portion of the drive the problem being it wasn't powering up.

 

After drawing further schematics we found it was through an 8k 70w resistor working as a potential divider that then fed the PWM (Pulse Width Modulation) chip on the SMPS (Switched Mode Power Supply). But the voltage was too low for the switch mode power supply to work. We needed to make a repair.

 

After disassembling the drive and reverse engineering the low voltage portion of the drive we were able to trace the PWM chip's voltage input to one of the input connectors and also off to what seemed to be a shut down optocoupler circuit from the control card. Investigating further we found a 400 ohm resistance across VCC and OV leading us to start pulling and investigating components. Surprisingly there was a SOT-23 SMD transistor that was not fully open or shorted across collector and emitter which was measuring 1.2k ohms. This was the culprit, after changing this part the voltage was restored and the low voltage portion of the drive was repaired.

 


It's hard to believe that a component (see right in the middle of the picture) the size of half a grain of rice could stop an entire factory from working! This is why you need ENA Electronics to be your Industrial Repair and Reverse Engineering company of choice, we go the extra mile and don't give up on those extra difficult repairs. For more information on the work we do head to our repair page, check out our catalog or get in touch for more information.

How To Clone (Snarf) A Secured IC

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Sometimes we get programmed ICs which cannot be duplicated by conventional means as the ICs have been secured at programming time which stops unauthorised copying. Unfortunately when a manufacturer goes out of business this proprietary code is lost + if the code was secured on the programmed IC then the only solution is to reverse engineer the functionality of the IC.

 

We have experience in external interface analysis (the black box approach) reverse engineering which is where an IC is probed on its inputs + outputs, inputting a signal onto one pin + detecting any changes on the output for this we use our custom black box tester which we developed just for this purpose.

 

If you really need we can even do silicon die analysis + work out how the chip is working through a microscope, this is a very time consuming process but can yield some interesting results.

 

In other situations when we are unable to probe inputs + outputs we have the necessary skills to either simulate the whole system + produce a working replacement (such as developing custom firmware). This process is generally involves re-developing the circuit or at least part of it.

 

Luckily at ENA Electronics we have the skill to recover your firmware! Get in touch with us for a free no obligation quote.

How to Clone or Snarf A Programmed IC

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As mentioned in our previous blog post on Cloning Copying + Duplicating IC’s blog post some IC’s are easier to clone/copy than others.

 

After a study of the market + ensuring that the IC/PCB is indeed obsolete we will first take your PCB + check that we can clone/copy any programmed ICs on the PCB. We do this by checking the make + model of each programmed IC, these part numbers are usually stamped on the top of the IC + we check it against our database of IC’s that can be programmed. We ensure we can source replacement parts + extract the machine code or hex code from the IC ensuring the chip revision + speed is matched or exceeded. Sometimes we receive IC’s which are not standard pinouts or packages - in such cases we make adapters to convert the IC into the universal programmer adapter type.

 

Once the code is extracted we view the checksum + view the hex code using a hex viewer in order to ensure data has been read. In 99% of the cases when we see data in the hex file we can duplicate the IC + this allows us to then program a blank IC that we have sourced.

 

Assuming the cloning process above is successful then the code will work identically to the original IC, will be just as reliable + its functionality is tested in the circuit. The whole process is nondestructive + allows us to copy the original IC without any damage to the original so rest assured your working IC will stay working!

 

We can help you with your old + obsolete IC cloning, get in touch to see how we can help you.

Cloning, Copying + Duplicating ICs + Microcontrollers for Reverse Engineering

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The heart of modern electronics is often a programmed IC (Integrated Circuit) thus the most important step when reverse engineering a PCB is to clone or copy the programmed IC’s. It should be noted that this process is only done after a thorough check to see if the PCB or IC is available, as this is proprietary code + can cause legal issues. You can only proceed given you are not breaching any IP or patents.

 

The concept of programmed IC duplication is to extract the machine code (often called HEX code) from the original programmed circuit + then write this code back onto a new IC which is critical in order to produce a duplicate PCB.

 

As electronics have got more complicated, circuit designers use integrated circuits to simplify + add functionality to a circuit. One example, is the use of Complex Programmable Logic Device (CPLD) to remove dozens of logic gates from a circuit by creating them on one chip thus saving cost time + circuit board real estate.

 

Before the days of microcontrollers circuit designers would use microprocessors, Read Only Memory (ROM) + Random Access Memory (RAM) to do the same thing. The ROM is where the program is stored + when reverse engineering a PCB with ROM on board these ROM’s need to be copied, luckily most universal programmers carry the older types of ROM + the programs are very rarely protected.

 

As technology has advanced Electronically Erasable Programmable Read Only Memories (EEPROM) have appeared, these often are used to store parameters or settings for a microcontroller, in general these can all be read using a universal programmer.

 

Microcontrollers are one of the hardest things to work with when reverse engineering a PCB this is because it is extremely easy to secure/copy protect a microcontroller. Often a designer will secure the device when programming it the first time so that it cannot be read properly by a universal programmer. If this is the case then there are ways around this, however, they are generally quite time consuming + involve manually probing each pin + rewriting the programming. It is very common to find microcontrollers on a PCB next to their programing headers - often these programming headers can give a clue to how the designer programmed the device + can sometimes be used for extracting the firmware. Although there are many microcontrollers on the market the main two microcontroller brands are: PIC microcontrollers which generally use the In Circuit Serial Programming (ICSP) interface + Atmel microcontrollers use the In Circuit Emulator (ICE) header.

 

Field Programmable Gate Arrays (FPGA)s are another type of programmed chip that are more common on more costly electronics + generally on newer electronics. FPGAs are often more complicated to duplicate as they normally have proprietary software/hardware suites + are commonly programmed over (Joint Test Action Group) JTAG or with a special programmer + cannot be read using a standard universal programmer.

 

If you need help to duplicate your programmed IC then get in touch, we’d love to help!

Reverse Engineering of PCB's + Electronic Circuit Boards

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Reverse Engineering a printed circuit board (PCB) is a process that takes time, dedication + skill, it certainly isn't for the faint of heart. A simple search online won't give you all the answers you need, to learn the entire process takes years of experience especially for complicated boards + circuits with obsolete components, it requires studying how other people design circuits + knowing exactly why they designed a circuit a certain way.

 

There are many reasons why we would want to reverse engineer a circuit board, one of the biggest reasons is that often factories have multi-million dollar machine systems that can be taken down by one component. Due to the initial cost of these machines they are often used for many years + if the OEM (Original Equipment Manufacturer) goes out of business + the machine is still needed then the factory is stuck with a multi-million dollar machine with no support or ability to repair it. In many situations like this it can be 15, 20, even 30 years after the machine was installed + all that is wrong with the machine is that one or two PCBs need repair or replacement. It's at this point we step in, not only have we got the capability to repair the original board, we can reverse engineer the board allowing the factory to have spare parts + support for what was an obsolete circuit board. Not only that we can upgrade the board adding extra features or changing current features we source currently available parts replacing all obsolete parts with a modern equivalent allowing for easier repair in the future + better support.

 

If required the schematics + board layouts can also be given to the customer in order to ensure that the PCB doesn’t become obsolete in the future. We keep the design files for you meaning that if you ever wish to repeat an order with us we can do it quickly + effectively.

 

We love electronics and are passionate about reverse engineering. Let us talk to you about why you should reverse engineer a circuit board and not just get a new machine!

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